It is oftentimes desirable to maintain or analyze an apparatus to enable correct operation and/or to provide an indication of faults therein. Often, such an apparatus is self-correcting with the fault indications being automatically utilized by the apparatus to make the necessary corrections where possible.
Assurance of correct operation of the apparatus is particularly important in many instances, including assurance of correct operation of an ink jet head in a printing machine. In such a machine, a valve is commonly opened to allow ink from a pressurized source to pass to the ink jet head with a resulting pressure build-up in the ink jet head. The speed of operation of the valve and the time required for pressure build-up in the ink jet head indicates the general condition of the valve and ink jet head. If the operation of the valve is slow (or if the valve fails to open) and/or if the pressure build-up within the jet head is slow, this can indicate faulty operation and obviously can result in poor printing quality.
While the prior art shows various start-up procedures for an ink jet head (see, for example, U.S. Pat. Nos. 3,618,858 and 3,891,121), as well as control of ink concentration (see, for example, U.S. Pat. Nos. 3,771,568, 3,930,258 and 3,828,172), there is no known showing in the prior art of a system or method for automated dynamic diagnosis of an ink jet head or recovery from a fault therein.